CVE-2026-31834CWE-269CWE-284CWE-862

Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks

High · published March 10, 2026

CVSS v3.1
7.2
EPSS
0%
Percentile
40.4
In the wild
Unconfirmed
What it is

Umbraco is an ASP.NET CMS. From 15.3.1 to before 16.5.1 and 17.2.2, A privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships. The affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles. This vulnerability is fixed in 16.5.1 and 17.2.2.

The record
Technical detail
CVSS v3.1
7.2 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00480 · 40.4th percentile
Weaknesses
CWE-269 · Improper Privilege Management; CWE-284 · Improper Access Control; CWE-862 · Missing Authorization
Published
2026-03-10T21:53Z
EPSS history
Timeline
  • 10 MAR 21:53Z
    Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
    cvelistv5